This invention relates generally to wellbore casings, and in particular to wellbore casings that are formed using expandable tubing.
Conventionally, when a wellbore is created, a number of casings are installed in the borehole to prevent collapse of the borehole wall and to prevent undesired outflow of drilling fluid into the formation or inflow of fluid from the formation into the borehole. The borehole is drilled in intervals whereby a casing which is to be installed in a lower borehole interval is lowered through a previously installed casing of an upper borehole interval. As a consequence of this procedure the casing of the lower interval is of smaller diameter than the casing of the upper interval. Thus, the casings are in a nested arrangement with casing diameters decreasing in downward direction. Cement annuli are provided between the outer surfaces of the casings and the borehole wall to seal the casings from the borehole wall. As a consequence of this nested arrangement a relatively large borehole diameter is required at the upper part of the wellbore. Such a large borehole diameter involves increased costs due to heavy casing handling equipment, large drill bits and increased volumes of drilling fluid and drill cuttings. Moreover, increased drilling rig time is involved due to required cement pumping, cement hardening, required equipment changes due to large variations in hole diameters drilled in the course of the well, and the large volume of cuttings drilled and removed.
Conventionally, at the surface end of the wellbore, a wellhead is formed that typically includes a surface casing, a number of production and/or drilling spools, valving, and a Christmas tree. Typically the wellhead further includes a concentric arrangement of casings including a production casing and one or more intermediate casings. The casings are typically supported using load bearing slips positioned above the ground. The conventional design and construction of wellheads is expensive and complex.
Conventionally, a wellbore casing cannot be formed during the drilling of a wellbore. Typically, the wellbore is drilled and then a wellbore casing is formed in the newly drilled section of the wellbore. This delays the completion of a well.
The present invention is directed to overcoming one or more of the limitations of the existing procedures for forming wellbores and wellheads.
According to one aspect of the present invention, an expansion cone for expanding a tubular member is provided that includes a housing including a tapered first end and a second end, one or more grooves formed in the outer surface of the tapered first end, and one or more axial flow passages fluidicly coupled to the circumferential grooves.
According to another aspect of the present invention, a method of lubricating the interface between a tubular member and an expansion cone having a first tapered end and a second end during the radial expansion of the tubular member by the expansion cone, wherein the interface between the tubular member and the first tapered end of the expansion cone includes a leading edge portion and a trailing edge portion, is provided that includes injecting a lubricating fluid into the trailing edge portion.
According to another aspect of the present invention, a method of removing debris formed during the radial expansion of a tubular member by an expansion cone from the interface between the tubular member and the expansion cone, the expansion cone including a first tapered end and a second end, the interface between the tubular member and the first tapered end of the expansion cone includes a leading edge portion and a trailing edge portion, is provided that includes injecting a lubricating fluid into the interface between the tubular member and the expansion cone.
According to another aspect of the present invention, a tubular member is provided that includes an annular member having a wall thickness that varies less than about 8%, a hoop yield strength that varies less than about 10%, imperfections of less than about 8% of the wall thickness, no failure for radial expansions of up to about 30%, and no necking of the walls of the annular member for radial expansions of up to about 25%.
According to another aspect of the present invention, a wellbore casing is provided that includes one or more tubular members. Each tubular member includes an annular member having a wall thickness that varies less than about 8%, a hoop yield strength that varies less than about 10%, imperfections of less than about 8% of the wall thickness, no failure for radial expansions of up to about 30%, and no necking of the walls of the annular member for radial expansions of up to about 25%.
According to another aspect of the present invention, a method of forming a wellbore casing is provided that includes placing a tubular member and an expansion cone in a wellbore and displacing the expansion cone relative to the tubular member. The tubular member includes an annular member having a wall thickness that varies less than about 8%, a hoop yield strength that varies less than about 10%, imperfections of less than about 8% of the wall thickness, no failure for radial expansions of up to about 30%, and no necking of the walls of the annular member for radial expansions of up to about 25%.
According to another aspect of the present invention, a method of selecting a group of tubular members for subsequent radial expansion is provided that includes radially expanding the ends of a representative sample of the group of tubular members, measuring the amount of necking of the walls of the radially expanded ends of the tubular members, and if the radially expanded ends of the tubular members do not exhibit necking for radial expansions of up to about 25%, then accepting the group of tubular members.
According to another aspect of the present invention, a method of selecting a group of tubular members is provided that includes radially expanding the ends of a representative sample of the group of tubular members until each of the tubular members fail, and if the radially expanded ends of the tubular members do not fail for radial expansions of up to about 30%, then accepting the group of tubular members.
According to another aspect of the present invention, a method of inserting a tubular member into a wellbore is provided that includes injecting a lubricating fluid into the wellbore and inserting the tubular member into the wellbore.